In a phase-control microwave communications technology, movement or scanning of antenna beam pointing in space is implemented mainly depending on a phase change. A phased array includes several parts such as an antenna array, a phase shifter, a feeder network, and a corresponding control circuit. The antenna array includes multiple antenna units, and a phase shifter is disposed at a rear end of each antenna unit and is used to change a signal phase of the antenna unit. Phase configuration of the phase shifter is controlled using a corresponding control circuit to form a transmit beam or a receive beam with a specific pointing. A transmitter (Tx) completes directional transmission using a phased array. Correspondingly, a receiver (Rx) also completes directional receiving using a phased array. A transmit beam is aligned with a receive beam by means of beam tracking to implement relatively high beamforming transmission quality.
In an existing phase-control microwave communications technology, in a beam tracking implementation process, beam tracking is performed at a fixed scanning speed and a scanning angle step size. During each tracking process, received signal powers corresponding to different beam angles are detected in sequence at an Rx. When a detected receive power is maximum, a beam angle at this moment is considered as a beam alignment angle. Then, configuration and phase shifting are performed on the phase shifter using a phase shifter control signal at this moment. Each time beam scanning is performed, there is a delay from the moment when configuration of the phase shifter is started to the moment when phase configuration of the phase shifter takes effect. A delay value depends on a time it takes for a control circuit to generate a phase shift configuration phase plus a delay of a radio frequency electrically controlled phase shifter. These delays occupy air-interface overheads of a corresponding size in an air-interface frame. The air-interface overheads corresponding to these delays and a phase estimation sequence in the air-interface frame occupy a fixed quantity of symbols in the air-interface frame.
In an existing phase control system, a higher scanning speed indicates a higher frequency at which a phase shifter is configured, better beam tracking quality implemented, and a shorter frame length of a corresponding air-interface frame. However, a quantity of symbols used for beam tracking is fixed, that is, a greater proportion of air-interface overheads used for beam tracking indicates less transmitted effective data, that is, lower transmission efficiency. On the contrary, a scanning lower speed indicates a lower frequency at which a phase shifter is configured, and a longer frame length of a corresponding air-interface frame. However, the quantity of symbols used for beam tracking is fixed, that is, a lower proportion of air-interface overheads used for beam tracking indicates more transmitted effective data, that is, higher transmission efficiency. However, relatively good beam tracking quality cannot be implemented.
In the phase control system of other approaches, high-speed mobile beam tracking can be performed only at a fixed scanning speed and a scanning angle step size. When a Tx and an Rx are relatively static or relatively distant from each other, a beam angle changes very slowly or even does not change. In this case, an excessively high beam scanning speed and scanning angle step size are not needed. If beam tracking is performed at a relatively high beam scanning speed and scanning angle step size, low data transmission efficiency is caused.